Psychonomic Bulletin & Review

, Volume 21, Issue 3, pp 689–695

Visual similarity is stronger than semantic similarity in guiding visual search for numbers

  • Hayward J. Godwin
  • Michael C. Hout
  • Tamaryn Menneer
Brief Report

DOI: 10.3758/s13423-013-0547-4

Cite this article as:
Godwin, H.J., Hout, M.C. & Menneer, T. Psychon Bull Rev (2014) 21: 689. doi:10.3758/s13423-013-0547-4


Using a visual search task, we explored how behavior is influenced by both visual and semantic information. We recorded participants’ eye movements as they searched for a single target number in a search array of single-digit numbers (0–9). We examined the probability of fixating the various distractors as a function of two key dimensions: the visual similarity between the target and each distractor, and the semantic similarity (i.e., the numerical distance) between the target and each distractor. Visual similarity estimates were obtained using multidimensional scaling based on the independent observer similarity ratings. A linear mixed-effects model demonstrated that both visual and semantic similarity influenced the probability that distractors would be fixated. However, the visual similarity effect was substantially larger than the semantic similarity effect. We close by discussing the potential value of using this novel methodological approach and the implications for both simple and complex visual search displays.


Eye movements Visual search 

Supplementary material

13423_2013_547_MOESM1_ESM.doc (80 kb)
Supplementary Table S1Two-dimensional MDS coordinates for each of the ten digit stimuli (DOC 80 kb)
13423_2013_547_MOESM2_ESM.doc (97 kb)
Supplementary Table S2MDS distances (in arbitrary units) between each pair of digits. (DOC 97 kb)
13423_2013_547_MOESM3_ESM.doc (184 kb)
Supplementary Fig. S1The plot on the left shows the data from Shepard et al. (1975). There, participants were shown Arabic numerals, two at a time, and were asked to rate the similarity of each pair (using a slide marker that comprised a 21-point scale). The plot on the left shows the present data, for which participants rated the similarity of the numbers using the spatial arrangement method (Goldstone, 1994). The x-axis coordinates for our data were reversed, to match the overall orientation of the Shepard data (the coordinate axes are arbitrary). In both instances, it is clear that the two dimensions used to rate similarity were curvature and the extent to which the numbers comprised open or closed spaces. (DOC 183 kb)

Copyright information

© Psychonomic Society, Inc. 2013

Authors and Affiliations

  • Hayward J. Godwin
    • 1
  • Michael C. Hout
    • 2
  • Tamaryn Menneer
    • 1
  1. 1.School of PsychologyUniversity of SouthamptonSouthamptonUK
  2. 2.New Mexico State UniversityLas CrucesUSA

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